It is known that higher olefins can be prepared by alkylating a lower olefin with an oxygenate.
For example, EP-A-0485145 describes a process for the production of olefins, selective towards C4/C5 olefins, which comprises passing an oxygenate containing feedstock over a zeo type catalyst at a temperature greater than 200° C., wherein the feedstock comprises C3 and/or C4 olefins and the oxygenate can be methanol, formaldehyde or dimethylether. The molar ratio of olefin to oxygenate is greater than 1:20 and the zeo type catalyst is of the TON-type structure. In the examples 1-butene and methanol are converted at temperatures of 300° C. and 400° C. over a so-called theta-1 zeolite, having a silica to alumina ratio of 68. A molar ratio of methanol to olefin of about 4:1 is exemplified. The selectivity towards C6+ ranges between 43.1 and 48.4% based on carbon molar converted. This C6+ product, however, also contains C7+ compounds.
US-A-2003/0181777 describes a method for reducing the formation of undesired heavy hydrocarbons when catalytically cracking a heavy olefin containing feedstock to a light olefin product by employing an oxygen containing hydrocarbon as a co-feedstock. A preferred feed consists of C4 and/or C5 olefins. The molar ratio of oxygen containing hydrocarbon to olefinic feed is preferably less than about 1/1. In example 2, methanol and butenes are co-fed over a MTT type zeolite at a temperature of 1022-1160° F. (550-627° C.) and a methanol/olefinic stream mole ratio of about 0.77 to prepare ethylene and propylene. The examples do not show the preparation of any C5 and/or C6 olefins.
It would be advantageous to have a process with an increased selectivity towards C5 and/or C6 olefins.